


Red and Blue Make Purple

by sheepwolves



Category: Undertale (Video Game)
Genre: Alternate Universe - Fusion, Alternate Universe - Undertale Fusion, Chara Being An Asshole, Chara Is Their Own Warning, Genocide Sans, Sans Boss Battle, Sans Has Issues, Undertale Genocide Route, this whole thing is just a big long fight tbh
Language: English
Status: Completed
Published: 2016-10-31
Updated: 2016-10-31
Packaged: 2018-08-28 01:43:28
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 3,365
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8425876
Author URL: https://archiveofourown.org/users/sheepwolves/pseuds/sheepwolves
Summary: Chara gets a cool new body with superpowers. Only problem is the body wants to keep them trapped in Judgment Hall forever. Au where Sans isn’t bluffing when he threatens to keep you “until the end of time” Read the note at the beginning for more info





	

**Author's Note:**

> Happy Halloween! This is a fic where Sans makes a different decision and tries a lil bit harder to keep the timeline from being destroyed. he fuses with chara to try to keep them trapped within the fusion until the end of time, or at least until they reset. Whichever comes first. It’s a bit out of character but eh who cares.

Sans couldn’t afford to just focus on maintaining consciousness with a killer prowling ten feet away, but it was getting more and more difficult to function when the world was faltering around him. His vision was beginning to blur at the edges like an old photograph. Spine curved downward, legs trembling from the effort of standing upright, he watched the human pace like a predator, unsoiled knife glinting against the light seeping through the towering stained glass windows. For a brief second, he envisioned a smear of blood obscuring his reflection against the silver.

This had to end.

“So, uh, in my personal opinion…” He breathed, blinking away the blackness blotting his line of sight. “The most determined thing you can do here? Is to, uh, completely give up. And…” He stifled a yawn, eyes still trained on the murderer, “…do literally anything else.”

 Perhaps if he just rested his hands on his knees…

The human lunged only to be deflected with a slash of cerulean defensive magic. No rest for the wicked, he supposed…

Droplets of sweat flecked to the tiled floor as he dragged the back of his shaking hand across his drenched forehead. There was a slim possibility they’d make it this far, but he wasn’t prepared for the situation being realized and he was quickly running out of cards to play. Bluffing would only take him so far empty-handed. He needed to think…

With a battle cry that echoed through the corridor, the human threw themselves at him again, and was once more pushed backward with a flimsy wave of magic.

The unquenched impulse to kill the human still wracked his bones like disease, but he lacked the stamina to produce even one more offensive attack. As long as he made sure the human kept their distance, he could defend himself all day, but if they got close enough…

He swallowed hard. The human looked savage, unbridled rage pouring through their features. Exhaustion was evident, but they were still eager to kill. Matching their determination was out of the question.

What were they doing, trying to kill each other over and over and over again? What did the kid possibly have to gain from it? And how the hell was he going to stop them now that they’d bled him dry?

Heavy lids half closed, he heard their feet pounding against the floor and jolted awake, but this time…

Gut instinct guided his split second decision. Or maybe it was just the dread of having to fend off the human and stay awake until he made a mistake.

Either way, he watched them advance and waited, resigned to his own death. The predator rushed forward, claws unsheathed and ready to tear, and yet he stayed still. The blade pierced him straight through the chest with the force of a car crash, the explosion of pain and momentum nearly overwhelming him, but through sheer willpower he managed to dig his fingers into their arm to lock them into place. It would only be for a moment. The hard part was over.

Lashes of fiery blue magic climbed up his arm and encircled the two of them. The warm match-strikes pushed against their bodies and forced them closer, driving the knife farther in with an eerie scrape of metal against bone. He couldn’t tell the roar of magic from the guttural noises in his raw throat, or the sensations pounding against his skull from the murderer desperately flailing against his trap.

And it was too late.

Eyes flying open, he dragged the human downward with what strength he could muster, teeth gritted and locked eyes with their deranged expression. Through the distorted, blurry haze he could feel the wrath seething behind their face, singeing their skin.

 _“You’re done,”_ He wheezed, feeling the weight of his powers shoving them to the ground, creaking against his bones, and he wasn’t sure if he said it out loud or in his head, or even if it mattered as their souls overlapped and the world around them seemed to vanish in a whirlwind of dancing flames. _“_ You’re not going any further, even if it means we stay here _forever.”_

They sunk deeper into what couldn’t be considered the ground anymore, their thrashing body meshing together with his. The pain in his chest spread outward, heart leaping as he heard a shriek. Their very souls were touching, the colors blending into one, red bleeding behind a mask of _blue_.

He would not be overpowered, not once, not _ever_.

Pain hacked through his heaving, broken chest, and he spoke in a strained voice coated with freshly uprooted emotion, a newfound _determination_. “You better reset _now_ , ‘cause I’m _never letting you go.”_

Finally, violet wisps of writhing flame wreathed his hands and twisted snake-like around his face, blinding him, strangling him. A subduing, unanimous thought screamed in his… their head,

“ _What did you do?”_

…

Their eyes were cavernous, empty wells. The void in their sockets bled down their cracked skull in a nature-defying act on par with amalgams. Below the sockets, a grin stretched cemented to the mask placed upon their face. As they pried open their jaws, they found the mask lifted, below which resided a mouth lined with teeth each as deadly as the knife stuck in their chest, busted through their back. Upon attempting to push themselves to their feet, they found abandoned striped sleeves fell to the tile on either side of them.

Skeletal hands suddenly conjured themselves in a wisp of purple. A hole was punched through the palms, but each worked flawlessly even without arms to attach them. Finally, as they rose, a pair of something sliced through the air and stretched from their back with a strange flutter. Massive wings of a terrifying _angel_ , black as a crow, grazed the space above them.

This was untrodden territory. Emotions conflicted within their damaged skull, but there was certainly potential in this new existence.

Something pierced through the relative stability they had achieved, something blue as the surface sky. Their knees greeted the floor with a thud. Sharp phalanges scrabbled around and at their head, finding home along their throat and dug madly into the cleavages in their skull.

…

“I ponder your plan. Do you truly intend to imprison us here until the end of time?”

Across the abandoned, piceous stage, there was no answer.

Silence, he learned, could be as abrasive as any noise. It was nearly maddening, but preferable still to the child opposite him.

He took the precious moment to just breathe. Any opportunity to collect his bearings and channel his strength was to be seized. Remaining calm was important, he thought, closing his eyes. _Focus_ was key…

Still, he flinched as they spoke again.

 “You have deluded yourself with a perverse sense of self-sacrifice and you are unable to comprehend the immeasurability of the ‘end of time’. All you desire is rest. Give in to me. It is the absolute, the unavoidable outcome decided for you long before.”

The slow, quiet voice echoed eerily, slicing cleanly through the nothingness as if emanating from his own thoughts. It created the illusion that they were within striking distance, hovering just above, holding still just to taunt him. In reality, they were far enough away that the danger was not immediate, but oh, it was very much there… and he was so, so _tired_ …

“Do you believe, after all this time, that I am not more patient than you? That I will not lie and wait for the opportune moment to crush you?”

Somehow, their threats held much more water here. A shiver ran down his spine and sweat-soaked clothes. They were right of course, his own willpower wouldn’t hold them off forever, but he couldn’t afford to let them win in the end… it just wasn’t an option. What the hell was he supposed to do?

He pressed his forehead to whatever surface resided below them in this realm, and strained to shove them farther backwards, to tighten his tether on them.

“Y-you sure’ve got a lot to say ,” He rasped, ribs expanding and contracting painfully, choking down each breath. “Liked it better when you were dead…”

In having their souls merge, it wasn’t just the kid who learned a thing or two about Sans that he didn’t want them knowing. This was Chara, the first fallen child. Self-proclaimed demon, they were the will to experiment and kill, and thus the reason behind all those not-so-great timelines. They had been asleep for a long, long time. Only now were they awakened by the actions of this ‘third party’ who did most the killing. Now it was just them, and they were hell-bent on destroying this timeline with or without Sans clinging to their heel.

It was a lot to think about, and he had an eternity, but getting distracted would result in that eternity being cut short, most likely ending in oblivion, so he kept concentrated.

He sucked in what amounted to a lung full of air and feigned slurred speech, “Why don’cha just reset already, huh? I’m not real impressed with the whole… destroying worlds thing,” He hissed, taking a moment to readjust his magic. It was a risk trying to talk and keep them shackled to the opposite end of this playing field, but he had to try while he still could.

Keeling over slightly, a painful wince having clouded his expression, he waited a few full minutes. He could afford to take it slow. The child said nothing, apparently having sensed he wasn’t finished speaking until he finally resumed, “Like I said, there’s absolutely no benefit for ‘ya, so why not do me a favor, eh? You got t’ play with me… which was tons ’a fun… hows’ about givin’ ‘ol Sansy a break as a thank you? Please?”

The child chuckled. “Perhaps it is too abstract a concept for mere mortals to understand, but this is about so much more than RESETS. You were in my way. I got rid of you. All there is left is to wait for you to realize this is true.”

Looming defeat kissed his soul, bent his spine beneath the weight of it, and surely the other could feel it too.

“…Do you see the mistake you have made now? Stupid… you do not know the world as I do. You know nothing, yet you have convinced yourself you know everything. You are _weak_.”

He made an airy gesture, though his hand shook so erratically it was difficult to feel the sarcasm behind the motion.

“At least, determination was never something you pretended to possess...” They sighed, creepy smile never faltering. “Even now your grip on _my_ soul is slipping, and soon I will possess yours as well.”

…

Sleep did not come in this place. Food, water, even breathing didn’t _really_ matter (though it helped). There was nothing but the two of them.

He had collapsed long before, head bowed and panting like a dog, knees pressed to the ground, sweaty palms clutching, sliding against the floor. His limbs shuddered violently with the effort of holding his magic down, constantly exerting energy he did not possess. His will had shattered a few occasions, and just as promised the child had broken free and advanced towards him like pieces on a chessboard before he could shield himself once again and chain them where they stood. If he could be bothered to open his eyes, he would see their unwavering, striking crimson gaze bearing down upon him. It was far too close for comfort, their thin smile tugging at their mouth. Even without looking, he could feel the heat of it bearing down against his bones.

“…What are you?” They asked with a slight tilt of the head in the midst of their endless, timeless game. “Are you ever going to speak? Aren’t I supposed to be the child in this scenario, despite being far older and more experienced than you? You arrogant, stupid _thing_.”

Their voice and taunts had blurred to monotonous white noise.

For a single moment, his grip lapsed with a twitch of his wrists, and they strode closer, mockingly casual. Fear thrust him to action, and his shoulders hitched suddenly as he struggled to hold them back in place with a sharp, pained gasp. Jaw clenched, tears squeezed from his sockets and dropped into the nothingness below them.

God, he was just so _tired_. He needed only a minute, just a few moments of rest and he could keep going. Oh, how could this all have fallen on him? But it was alright, he could be alone here forever and it didn’t matter, or at least until this vile, unholy spawn of hell in horrifyingly close vicinity finally got bored… but somebody, _anybody,_ had to help him out, _please…_

But nobody came.

The child spoke before their thinly veiled excitement, “You are weary, bargaining with nothing. What is keeping you clinging to me like a tumor? After all this time, do you still believe you can overpower me? The demon, the angel, ME, who has and will destroy timelines beneath my will? Or perhaps is it that my own determination has somehow leaked into you with our newly merged souls?” They crouched, barely a few arm lengths away, and studied him for a moment, taking in his decimated, quavering composure. The only noise was his unsteady breathing and the occasional scrabble of his hands against the floor. He could feel their evil gaze brushing against his very being. He knew they knew he was running off fumes.

“Haha… patience is a virtue,” They said, crossing their legs and placed their hands in their lap, leaning forward excitedly. “You will burn yourself out soon. Then it will just be ME. It has always been ME.”

…

The ropes snapped.

In a way, it was a relief. Reigning in such a powerful creature for so _ungodly_ long had been more than he could have ever accomplished on his own. The mere fact that he’d made it as far as he did was incredible, but what the hell possessed him to believe he would be able to successfully bully them into resetting? That he was ever strong enough? Really, it was just that once he had fused he wasn’t sure what to do other than hold them down as long as he could. There was never really a plan, but he gave it his all anyway.

Barely aware of what was happening, his minimal relief was quickly smothered upon watching his fate seal itself. The predator approached silently, his fear mounting with each of their slow, deliberate steps.  

On desperate instinct, eye glowing weakly like a dying candle, he tried to throw out wisps of lifeless magic that latched limply onto the child. They moved forward unruffled, kicking his lame attempts away like dust from their shoes. And still they smiled.

“Tell me… where has your apathy gone? Has it not been carved into your feeble soul? I have gotten to know you quite well in this place… this void,” They gestured to the endless black tomb around them and turned to him with an almost pondering expression. “I know you better than you know yourself.”

He wanted to get away, to disappear, to _die_ , but the demon prowled still closer. Too weak to cower, too tired to fight, he waited on bated breath, eyes stretched wide against a terror he had never known. It engulfed him like an impenetrable ocean, bleak and quelling.

Their very presence, so close and inescapable, was that of such unrepentant evil, such soul crushing malice, he was surely drowning in their wake.

Pent up passion seeped through their tone with every step, “You, so young and ignorant, have seen so much, and all your pain is _me._ I feel your rage. Your hatred. Your horror. How I _haunt_ you waking day and night. How I _torture_ you. You see me in your nightmares. In your fragmented memories. In your worst fears that even you do not understand.”

Icy hands, cold as a corpse, gripped the sides of his skull. His own suffocating exhaustion seemed to melt, replaced by something indescribably worse. They clutched his face tight and forced his skull upwards so the wide smile and glinting, blood red eyes were all he could see. Would it be the last thing he saw?

The childishness had entered their tone now, and their hands trembled with the flood of emotion, fingers digging into his face. “I want you to scream to me. Tell me of what I have done to you, how I have cracked your bones and crushed your spirit, how I made you hollow and beat the hope from your soul.” They pressed their forehead to his, and he could feel the glee reeking from beneath their skin, their vicious intentions rotting in their heart.

“Cry for me, because you want nothing more than rest, and I will not let you die. Because you, of all the miserable monsters, you wish to forget, but only you are forced to remember. Because of that, you burdened yourself with the responsibility of saving this doomed timeline that could never have been saved, but _SINCE WHEN WERE YOU—“_

“You’re a real freak, you know that?” He muttered, too lethargic to be surprised he’d successfully managed to interrupt them. Their expression actually faltered, and they withdrew, waiting for him to continue to what would probably amount to be his last words. “Ah… just cut the edgy crap and eat my soul or somethin’. I really don’t appreciate you draggin’ this out for someone who’s ultimately gonna be unimpressed, alright?”

They feigned amusement, and shrugged.

“Well, eternity awaits with ME either way,” They murmured lovingly, an inhuman grin cracking across their face as they let out a shrieking laugh that washed over his senses as blackness consumed his vision.

And the hands were gone. The ground had opened up beneath and swallowed him whole. He was falling into nothingness, weightless, senseless. The dread and exhaustion seemed to drain the farther he delved… the emptiness rushed up to catch him… and finally he could close his eyes it seemed, as if he had a choice… and he was falling….

…

The creature moved like a glitched model. Limbs shifted and jerked seemingly involuntarily, the smiling, chipped mask lulled, revealing glimpses of the jaws beneath. The wings flapped madly or dragged along the ground with each slow, zombie-like stride so the charcoal feathers picked up loose gravel, dirt, and dust.

As gusts blew through the abandoned garden, empty sleeves flapped like a scarf on either side of them. Their head was angled downwards toward the trembling, familiar flower before them. He seemed too petrified for words.

Wings reached like open arms, flecked with splashes of fresh, cloud grey that sprinkled to the ground below. The flower did not break contact with the black-hole sockets, but the sudden movement seemed to spur him to whimper, “Y-you aren’t Chara…. Wh-who are you?”

A corrupted, volatile voice answered, “ITS ME YOUR ~~BEST FRIEND~~ OUTTA MY WAY, KID.”

The body flung forward, wings flexing as the gaping mouth along the chin fully unhinged, vomiting a raw beam of magic. With a startled yelp, the flower dived into the ground far too late. Skeletal hands coated in a veil of opaque violet plunged forward, grasping the thick stem from the dirt and ripped the flower upwards in a violent jerk. The wet snaps of severed roots were drowned within his terrified shriek. “WHAT, ARE YOU TRYING TO RUN AWAY? TRYING TO _LEAF_ ME ALL ALONE? YOU HAD IT COMING LONG AGO.”

The flower was sobbing, screaming in desperation, “It’s _me_ , Chara! _Please_! I can help, I can—”

The mask swung forward as the jaws spat a torrent of purple magic that consumed Asriel, writhing and twisting like a snake within their hands, until he was nothing but a charred crisp. The scent of burnt vegetation wafted through the ai—

 

 

 

**A FATAL ERROR HAS OCCURRED.**

**The application has encountered a critical error. Click on OK to terminate the program.**

**OK ~~KEEP PLAYING~~**

**Author's Note:**

> Notes at bottom: I don’t know how I feel about this story? It’s a little weird and abstract, but anyway, take this poll on whether I should write another chapter or not, if u want <33  
> http://vote.pollcode.com/64181612


End file.
